Sintering temperature, too high temperature will make titanium carbide grain growth speed. Titanium carbide high manganese steel bonded carbide final sintering temperature generally take 1420 ℃ more appropriate. Titanium plate manufacturers think sintering temperature should not be too high. Even the bond phase into liquid phase metal loss, so that the hard phase adjacent, aggregation and grow up, forming a source of fragmentation. This is the reason why the bonding phase between hard phase grains analyzed above becomes less.
Of course, the sintering temperature should not be too low, otherwise, the alloy will be underburned. In addition to the above-mentioned need to control the sintering temperature and speed, the furnace vacuum, into the liquid phase sintering phase. In addition, the vacuum degree in the sintering furnace should be controlled, because too high vacuum degree will make a large amount of liquid phase metal volatilize, resulting in component segregation. Especially in the three stages of degumming, reduction and liquid phase sintering, the heating rate during sintering is higher than that during sintering.
The heating speed and holding time should be strictly controlled. Because in the low-temperature degumming stage, the compaction releases the pressing stress and the forming agent volatilizes the process. If the heating speed is fast, the forming agent has no time to volatilize and turns into steam after liquefaction, which causes the compaction to burst or slightly crack. Above 900 ℃ reduction stage, to make compact have enough time to take off all use the raw material powder (such as Mn2Fe intermediate alloy) in volatiles and oxygen; When entering the liquid phase sintering stage, it is necessary to slow down the heating rate to make the compaction fully alloying.
Under the same condition, the decarburization behavior of industrial titanium plate with different components is different. For example, Si can improve the elastic limit, strength, tempering stability and elasticity reduction resistance, because different alloying elements have different effects on the activity and diffusion of carbon. However, more attention should be paid to the surface decarbonization caused by the increase of carbon activity and chemical potential gradient of Si in austenite.
Titanium plate manufacturers believe that the surface strength of parts is an important factor affecting fatigue strength. Surface heat treatment and surface cold plastic deformation machining is very effective for improving fatigue strength. Reduce fatigue crack formation. The surface decarburization layer produced by heat treatment can significantly improve the fatigue limit. Without removing the surface decarburization layer after heat treatment, the direct shot peening has a larger range than the shot peening after removing the decarburization to improve the service limit, such as surface quenching, carburizing, carbonitriding, nitriding, shot peening and rolling.